[coverage] clamp to binary before merging.

R=jgruber@chromium.org

Change-Id: Iad6f815d2476c59a498b7f580ec664417e83c675
Reviewed-on: https://chromium-review.googlesource.com/600050
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47197}

src/debug/debug-coverage.cc

@@ -354,6 +354,9 @@ void CollectBlockCoverage(Isolate* isolate, CoverageFunction* function,
   function->has_block_coverage = true;
   function->blocks = GetSortedBlockData(isolate, info);
 
+  // If in binary mode, only report counts of 0/1.
+  if (mode == debug::Coverage::kBlockBinary) ClampToBinary(function);
+
   // Remove duplicate singleton ranges, keeping the max count.
   MergeDuplicateSingletons(function);
 
@@ -371,8 +374,6 @@ void CollectBlockCoverage(Isolate* isolate, CoverageFunction* function,
   // Filter out ranges of zero length.
   FilterEmptyRanges(function);
 
-  // If in binary mode, only report counts of 0/1.
-  if (mode == debug::Coverage::kBlockBinary) ClampToBinary(function);
 
   // Reset all counters on the DebugInfo to zero.
   ResetAllBlockCounts(info);

test/inspector/cpu-profiler/coverage-block-expected.txt

@@ -844,16 +844,6 @@ Running test: testPreciseBinaryCoverage
                                 startOffset : 1
                             }
                             [1] : {
-                                count : 1
-                                endOffset : 41
-                                startOffset : 32
-                            }
-                            [2] : {
-                                count : 1
-                                endOffset : 71
-                                startOffset : 41
-                            }
-                            [3] : {
                                 count : 0
                                 endOffset : 72
                                 startOffset : 71
@@ -938,14 +928,9 @@ Running test: testPreciseBinaryCoverage
                                 startOffset : 1
                             }
                             [1] : {
-                                count : 1
-                                endOffset : 41
-                                startOffset : 32
-                            }
-                            [2] : {
                                 count : 1
                                 endOffset : 71
-                                startOffset : 41
+                                startOffset : 32
                             }
                         ]
                     }

test/inspector/cpu-profiler/coverage-expected.txt

@@ -633,16 +633,6 @@ Running test: testPreciseBinaryCoverage
                                 startOffset : 1
                             }
                             [1] : {
-                                count : 1
-                                endOffset : 41
-                                startOffset : 32
-                            }
-                            [2] : {
-                                count : 1
-                                endOffset : 71
-                                startOffset : 41
-                            }
-                            [3] : {
                                 count : 0
                                 endOffset : 72
                                 startOffset : 71
@@ -727,14 +717,9 @@ Running test: testPreciseBinaryCoverage
                                 startOffset : 1
                             }
                             [1] : {
-                                count : 1
-                                endOffset : 41
-                                startOffset : 32
-                            }
-                            [2] : {
                                 count : 1
                                 endOffset : 71
-                                startOffset : 41
+                                startOffset : 32
                             }
                         ]
                     }